How many pings? (IE6)

Im having trouble getting my VB app to detect if its online or not (I have a question about that in the VB section), however, my current working method relies on using ping to see if some websites are available.

However, one thing that concerns me is the amount of times i'll be pinging a site. Are there any limits on the number of times you can ping a website (google, amazon, bbc etc) before they start getting concerned or can I ping to my hearts content and it will be ignored?

Re: How many pings? (IE6)

Why don't you ping your ISP? You could also ping time.nist.gov - which supplies a check for internet time throughout the world. Neither is likely to object to a constant pinging. While it is unlikely, the sites you mention could go down from a DDOS attack. I doubt that they would object to a constant pinging. HTH

Re: How many pings? (IE6)

Thanks for your replies.

We provide a piece of marking software to about 500 reps around the UK. They synchronise with their main database at our site. I was using a windows API to check the connection but it doesnt work properly (only detects as the program is launched).

Until I find some working VB that checks if the user is online i'm using a module that pings 10 websites (mostly big ones least likely to go) and as soon as it successfully pings one (the first, assuming that site isn't down) it quits the module returning true (as there is a connection). If it gets through all 10 without a successful ping it will return false.

Our users are prone to connection issues so the program checks internet availability throughout the synchronisation process, therefore theres probably about 100 pings in the space of 10 minutes from one user synchronising (they generally dont do it any more often than once a day and alot do it less than that).

That time site sounds like a good one to use so I might put that at the top of the list. I can't really ping the ISP as all of the users use various ISPs. I suppose I could make the list from just ISPs rather than popular websites.

Hopefully its just a temporary measure, but if it would cause problems with users then being blocked from the site they are pinging, it would be a temporary measure I couldnt really use!

Re: How many pings? (IE6)

Presumably there's an "internal" security policy that precludes them pinging the IP address for your site - such as the firewall being set not to repond ti external pings? After all, connectivity elsewhere's not much good if they can't get to the main DB for synching. <img src=/S/smile.gif border=0 alt=smile width=15 height=15>

Re: How many pings? (IE6)

I knew that an incoming ping could be blocked (i.e. a website can be set up not to return if someone outside pings it). However, It hadnt occured to me that ping can be blocked by a clients firewall i.e. my ITdept change the firewall so I can't ping any websites at all - Now theres a pretty big spanner in the works!!!

The general process is: First the process determines if an internet connection is available, later it tries to connect to our FTP site, then attempts to List, download from it and upload to it - as each element of that can be blocked at firewall level.
We didnt want to use the same test to see if the user is online and to see if our FTP site is available as we need 2 distinct messages i.e. No internet connection. FTP site not avaialbe.

There must be an easier way to see if a user is connected to the internet - unfortunately my post in the VB section hasnt yet returned results and all of my searching on the net has resulted in the same solution that i've already found doesnt work properly. The search continues...